BACK TO WORK: Chris Stewart, who has a chance to be the Yankees’ starting catcher, takes batting practice Friday at the team’s minor league complex.N.Y. Post: Charles Wenzelberg

TAMPA — Not many people believed Chris Stewart would get a chance to be the starting catcher for the Yankees this season.

Not even Chris Stewart.

“I just assumed [Russell Martin] was coming back,” Stewart said.

Even when Martin decided to sign with Pittsburgh, last year’s backup was sure the team would find a new backstop to start ahead of him.

“You always do,” Stewart said. “It’s the Yankees. They always have a Plan F. But we let Russell go and it was a thin [catching] market this year.”

That leaves Stewart vying for more playing time, along with Austin Romine and Francisco Cervelli.

“I’m pumped,” said Stewart, whose solid work behind the plate has helped him stay in the majors despite a career OPS of just .583. “It’s a new chapter for me. I’m not used to actually going in and having a shot to be a starter. … It shows they have confidence in the guys we have here.”

Perhaps, but it also shows how much the Yankees have changed recently.

As team owner Hal Steinbrenner said Friday, his goal is to get payroll under $189 million by next year to avoid the luxury tax. That means battles like the ones the Yankees are set to have to find a catcher this season may become more commonplace.

But even more importantly, they need some of their younger players to stay healthy and actually become more than just prospects.

Because regardless of how well Stewart, 30, plays defensively, he’s not one of the keys to the Yankees’ future.

Manny Banuelos, however, is.

The 21-year-old isn’t expected to pitch this season while he recovers from October Tommy John surgery. The team’s former — and perhaps present — top prospect started playing catch last week and said his rehab is going well. Better, at least, than what he went through a season ago.

“My frustration started when I started missing my starts,” said Banuelos, whose elbow began bothering him in May. “It took a long time to make the decision to get the surgery. I know the Yankees [didn’t] want to do that.”

Banuelos said he is pain free and confident he will get back to where he was before the operation.

“I feel like [I’ll be] the same or better, but not worse,” Banuelos said. “I just want to come back [and pitch well].”

Banuelos isn’t the only young player working his way through rehab that the Yankees are counting on in the future.

Mason Williams said he will be ready to play this spring after surgery on his non-throwing shoulder last year after he hurt himself diving for a ball.

Though Williams, also 21, hasn’t played above Class-A ball, even the outfielder is aware of the $189 million payroll goal.

“I do hear that,” Williams said. “I don’t really follow it much. In my head, it doesn’t really matter. I still have to go out there and perform every day. I still have to do the things to get there. When the time comes, we’ll see where I’m at.”